R. Mewar et Fa. Mcmorris, EXPRESSION OF INSULIN-LIKE GROWTH FACTOR-BINDING PROTEIN MESSENGER-RNAS IN DEVELOPING RAT OLIGODENDROCYTES AND ASTROCYTES, Journal of neuroscience research, 50(5), 1997, pp. 721-728
Insulin-like growth factors, IGF-I and IGF-II, are potent regulators o
f oligodendrocyte development, Most of the IGF present in vivo is boun
d to members of a family of six high-affinity IGF-binding proteins (IG
FBPs), which can either potentiate or inhibit IGF action, depending on
other conditions, Additionally, serum contains a structurally unrelat
ed protein, acidlabile sub-unit (ALS), which forms a ternary complex w
ith IGF and IGFBP3, In this study, we used reverse-transcriptase polym
erase chain reaction (RT-PCR) to examine the expression of mRNAs for I
GFBP 1-6 and ALS in purified populations of oligodendroglial cells and
astrocytes, We found that astrocytes express all six IGFBPs, A2B5(+)/
O4(-) oligodendrocyte precursors, O4(+)/O1(-) intermediate precursors,
and O1(+) oligodendrocytes express IGFBP3, 5, and 6, while IGFBP4 is
expressed in oligodendrocyte precursors but not at more mature stages,
We were unable to detect ALS mRNA in whole brain or in cultured oligo
dendroglial cells, The presence of differentially expressed IGFBPs in
developing oligodendrocytes and astrocytes could significantly affect
the biological activity of IGF-I and IGF-II in the central nervous sys
tem and the IGF-responsiveness of the IGFBP-expressing cells. (C) 1997
Wiley-Liss, Inc.